birdsfandomcom-20200222-history
Gadwall
Gadwalls are commonly overlooked birds, but many birders consider this duck one of North America's most elegant species. Appearance Male Gadwalls are finely patterned with grey, brown, and black. They have a black rump patch, black bill, yellow-orange legs, and a brown, rounded head. While flying, a conspicuous white patch on their wings are visible. Females have a brown, scalloped back, a white wing patch, and dark eyestripe. The bill is dark orange instead of black. Both have whitish bellies and mostly white underwings. This species is about the same size as a Mallard, but slightly smaller. They are 18-22 inches (46-57 centimeters) in length with a wingspan of 33 inches (84 centimeters). They weight 18-45 ounces (500-1,250 grams). Occurrence This duck is common and widespread through North America. It occurrs from the western prairie pothole region of Canada and northern United States to isthmus of Mexico, the Gadwall's range has expanded as it adapts to man-made bodies of water. In winter, it is mostly found on lakes, marshes, and along rivers. Life History Diet Gadwall eat mostly submerged aquatic vegetation, including leaves, stems, roots, and seeds. They also eat small invertebrates. During the breeding season, animal matter can account for nearly 50 percent of an adult Gadwall’s diet, but this proportion drops to only about 5 percent animal matter during winter. Nesting Gadwall pairs form during fall migration. Once they return to their breeding grounds, they select their nest site while flying low over dry, grassy areas. The female makes a closer inspection on foot while the male stands guard near her. They typically choose dense brush or grasses at least a foot tall, usually within 200 yards of open water, and nest on islands when possible for greater safety from predators. In heavily cultivated areas, untilled land for nest sites can be a scarce resource. After the nest site is chosen, the female scrapes out a hollow, then settles into the nest and reaches out to grab twigs and leaves with her bill. She sets these against herself to form the base of a nest cup, then plucks her own down feathers to make an insulating lining. The finished nest is about a foot across with a cup 3 inches deep. It takes 5–7 days to go from looking for a nest site to having a finished nest ready for egg laying. Gadwalls lay 7-12 eggs per clutch, one egg per day. They produce only one brood per year. The eggs are 1.9-2.4 inches (4.9-6 centimeters) in length and 1.3-1.7 in (3.4-4.4 cm) in width. Gadwall incubation periods are 24-27 days and nesting period is 1-2 days. At hatching, hatchlings are alert, fully covered with down, eyes open, and ready to leave the nest in a day or two. Behavior Gadwall are dabbling ducks; they ride fairly high in the water and they tip forward to graze on submerged plants that they can reach with their outstretched necks. They rarely dive. Gadwall sometimes steal food from American Coots and other ducks. Like most ducks they often form flocks, and they may be seen them fidgeting as they swim about each other. These movements are actually a complex series of displays that communicate pair bonds, levels of aggression, and degrees of interest among potential mates. For example, Gadwall may send warnings to each other off by lifting their chin or opening their bill at another bird. A male may seek a female’s attention by ruffling his head feathers, drawing the head close to the body, and then rearing up out of the water and pushing his head forward. Further courtship displays include the male arching his head over his back and then jerking forward while raising his tail and wing coverts; pushing his bill underwater and then quickly tossing water into the air while whistling; and rearing up while raking his bill through the water and whistling. A female may show her interest by arching her head and neck and repeatedly moving it forward and then to the side away from the male. As the pair bond strengthens, the two birds face each other and raise and lower their heads, chins up; or turn their head and place the bill behind the wing, as if preening. Courtship happens in fall and early winter; almost all females find mates by November. Gadwall are seasonally monogamous. Sounds Calls Male Gadwall make short, deep, reedy calls referred to as “burps,” given in steady succession or 2–5 at a time while flying. They also make high whistles. Females quack rather like Mallards, but with a slightly higher pitch and more nasal quality. Conservation Gadwall populations increased by over 2.5 percent per year between 1966 and 2010, according to the North American Breeding Bird Survey. The species is not on the 2014 State of the Birds Watch List. Gadwall are the third most hunted duck species (after Mallard and Common Teal), with some 1.7 million of them harvested in 2010. Slightly more than 1 in every 10 ducks shot by U.S. hunters is a Gadwall. Duck harvests are carefully managed, and Gadwall numbers are still strong in part because of the conservation of both wetlands and adjacent upland nesting habitat through the Conservation Reserve Program and the North American Waterfowl Management Plan, as well as the efforts of private conservation groups. Gallery Gadwall.jpg|Female Gadwall flight.jpg|Male and female in flight. Gadwall ducklings.jpg|Ducklings wings.jpg|Male Gadwall and Teal.jpg|Male with Blue-winged Teal|link=Blue-winged Teal brewer's duck.jpg|Mallard x Gadwall hybrid (Brewer's Duck).|link=Mallard Trivia * The oldest known Gadwall was a male, and at least 19 years, 6 months old. He was banded in Saskatchewan in 1962 and shot during hunting season in Louisiana in 1981. * Gadwalls are called Ánade Friso in Spanish and Canard chipeau in French. Category:Anseriformes Category:Aves Category:Bird Species Category:Anatidae Category:Anas Category:Birds of North America